Caisteal Grugaig is an Iron Age broch standing on a small rocky knoll on a grassy slope. The 'Glenelg Brochs' of Dun Telve and Dun Troddan are a few miles to the south. Caisteal Grugaig should not be confused with the 'semi-broch' known as Dun Grugaig which is also near Glenelg.
The broch has an external diameter of around 16.5 metres and an internal diameter of around 9.6 metres. The broch was built on uneven ground, so the natural floor of the broch has a slope. The entrance passage is on the northeast side and has a massive triangular lintel over the doorway. There is an elongated guard cell on the left side of the entrance passage.
The interior of the broch has two intramural rooms at ground level, one of which is a small, oval cell. The other is a long mural cell, or length of ground gallery, which has a blocked doorway. The sides of an upper room are apparent above the entrance passage. Also inside the broch is a doorway to the mural stair. The five steps of the stair lead up to a long landing which leads to the beginning of a second flight of stairs.
References:The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.